You may have seen a YouTube video in which Dr. Robert Lustig of UCSF opines that calories are irrelevant and that sugar is, in essence, the root of all dietary evil. If you are among the few who have missed it, you have perhaps caught Gary Taubes' "what he said" article in the New York Times Magazine.
The notion that sugar is evil and the only dietary consideration that matters is, in a word, humbug.
Sugar, concentrated into the nectar of flowers, fuels the flight of hummingbirds. It is, in fact, the sole food source of these marvels of both aviation, and metabolic intensity. How evil can hummingbird fuel be?
Clearly not evil at all for hummingbirds! But that may not say much about us. So enough about hummingbirds; let's talk about you and me.
We were born with a preference for sweet because that has fostered the survival of not only Homo sapiens, but mammals in general, for perhaps as long as there have been mammals. Breast milk -- and I trust no one is foolhardy enough to suggest that breast milk is evil! -- is a sugar-sweetened beverage.